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AJvYcCUd2+Yc4NT8AuyYc5WKQ6bs+erwlrzp5qwHcF3jKOX2zX+fY6d/3zbGtTyJF27ypXFkF25FjOlaTg==@kvack.org X-Gm-Message-State: AOJu0YxmwPWQu41mjNLkyVNiqQvdYzQfuyJ7NDYNC/c4XAiujUeBKlE/ WzyuZGOUR+lYTc/ZSkaxjI8W/YtEfRX3hATQSSOaWfqc88L3kPaO4CU1tQsMu3E= X-Google-Smtp-Source: AGHT+IETLNjbMtdResL0gCQrMShCwCpeGL/L1zL6e1zJRM+ER4woSJMvk4wtR2Cz+Z4m4+aIJL98tA== X-Received: by 2002:a17:90b:4c8d:b0:2cb:50b8:e59d with SMTP id 98e67ed59e1d1-2d5e99a5e05mr2805975a91.12.1724228400217; Wed, 21 Aug 2024 01:20:00 -0700 (PDT) Received: from C02DW0BEMD6R.bytedance.net ([203.208.167.150]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2d5eb9049b0sm1091453a91.17.2024.08.21.01.19.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 21 Aug 2024 01:19:59 -0700 (PDT) From: Qi Zheng To: david@redhat.com, hughd@google.com, willy@infradead.org, muchun.song@linux.dev, vbabka@kernel.org, akpm@linux-foundation.org, rppt@kernel.org, vishal.moola@gmail.com, peterx@redhat.com, ryan.roberts@arm.com Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, Qi Zheng Subject: [PATCH 05/14] mm: khugepaged: __collapse_huge_page_swapin() use pte_offset_map_readonly_nolock() Date: Wed, 21 Aug 2024 16:18:48 +0800 Message-Id: X-Mailer: git-send-email 2.24.3 (Apple Git-128) In-Reply-To: References: MIME-Version: 1.0 X-Rspam-User: X-Rspamd-Queue-Id: AE4F720002 X-Rspamd-Server: rspam01 X-Stat-Signature: onozknbitzmyhqi5wdt6ndnuxf9tskam X-HE-Tag: 1724228401-780620 X-HE-Meta: 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 KWrybNk0 elXWrCUlmTPo3FKj4E/LbcKbixlibfHUHNNNGd7COPrFqK5DAnqvSmLT0VDZ8FNRVTsdVf9nYF1PLM9sCwKP+91eEgOOxyh8OOAZr+3a2iz5oeazo5lWhUiCJGD6eIRCuOv48bqPLBtBPt9I5KoziWweL3F2wQNKG0Pc0ixgJEjV7WiyFpX5m8vZ9v0Jzm7scMe86tLU+F+mh0xt0Uq0w3adRWc2/QyKlvzWFhbAFJNk+9xUF8147rlea8qEVH04QjLjTe4Iy/PSlGAmcaftRURNKbGZ8Vgkc9L10ymW63y/zk6fZAM8kLvFEPrzw8FLEml96XMnoeBht9qSgnE8rP4CFZiwtTDBbS8RHHiaxf+sq00b7WggnFEUahsR1lhqFIVsd5ixKL6eGh4xIMSYm2dAWswykywsQxMmKCXBb1yThcTO8FgpZg41Q24FuvGygZv8d X-Bogosity: Ham, tests=bogofilter, spamicity=0.000004, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: In __collapse_huge_page_swapin(), we just use the ptl for pte_same() check in do_swap_page(). In other places, we directly use pte_offset_map_lock(), so convert it to using pte_offset_map_readonly_nolock(). Signed-off-by: Qi Zheng --- mm/khugepaged.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index cdd1d8655a76b..26c083c59f03f 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1009,7 +1009,11 @@ static int __collapse_huge_page_swapin(struct mm_struct *mm, }; if (!pte++) { - pte = pte_offset_map_nolock(mm, pmd, address, &ptl); + /* + * Here the ptl is only used to check pte_same() in + * do_swap_page(), so readonly version is enough. + */ + pte = pte_offset_map_readonly_nolock(mm, pmd, address, &ptl); if (!pte) { mmap_read_unlock(mm); result = SCAN_PMD_NULL;